1. Field of the Invention
The present invention relates to a toner bottle unit that replenishes toner to a developing device included in an image forming apparatus, such as a printer, a facsimile, etc., and an image forming apparatus including the toner bottle unit.
2. Discussion of the Background Art
In an image forming apparatus that visualizes a latent image formed on a latent image bearer using two component developer stored in a developing device, toner in the developing device needs to be replenished as image formation proceeds.
According to a conventional image forming apparatus, a toner bottle is employed to store and replenish toner to a developing device when the toner is consumed. In such an apparatus, a used up toner bottle needs to be generally replaced with a new by a user whenever the toner in the toner bottle is used up.
According to a conventional replacement operation described in the Japanese Patent Registration No. 3492856, when a used up toner bottle is to be replaced with a new toner bottle, a cap of a toner ejection outlet previously detached from the toner bottle is attached to the toner ejection outlet when the toner bottle unit mounting the toner bottle is initially attached to a prescribed position of the image forming apparatus body as shown in FIG. 38. Specifically, an operation lever 81 is swung to a direction shown by an arrow (a) around a rotational axis of the operation lever 81 as a swinging center, and a cap opener 82 grasping the cap is moved to a direction as shown by an arrow (b) in conjunction with the swinging of the operation lever 81, and the cap is attached to the toner ejection outlet 84. Then, as shown in FIG. 39, the operation lever 81 is pulled in a direction as shown by an arrow (c), and the toner bottle unit 80 is withdrawn to a prescribed position outside the image forming apparatus. Then, the used up toner bottle is replaced with a new toner bottle at the prescribed position. When the replacement of the toner bottle 85 is completed, a tip of the operation lever 81 is pushed in a direction as shown by an arrow (d) in FIG. 40. The toner bottle unit 80 is then attached to a prescribed position of the image forming apparatus body. Then, as shown in FIG. 41, when the operation lever 81 is swung in a direction as shown by an arrow (e), the cap opener 82 grasping the cap 83 is withdrawn in a direction as shown by an arrow (f′), thereby the cap 83 is detached. In this way, toner in the toner bottle 85 can be ejected to the image forming apparatus body while the toner ejection outlet is open as shown in FIG. 38.
Further, it is conventionally known that toner is finally replenished to a developing device in an image forming apparatus body from a toner container included in a toner bottle unit. An opening is arranged on the toner container to engage with the developing device, so that the toner is replenished to the developing device through the opening. In the opening, a shutter for opening and closing the opening is provided to adjust an amount of toner supplied to the developing device from the toner container. For example, Japanese Patent Application Laid Open No. 2006-259228 discloses a plate like opening mechanism with a shutter hinge construction for opening and closing an opening of a toner containing section. The surface of the shutter contacts the edge of the opening and closes the opening by covering thereof. In this way, when a toner bottle is to be replaced and thus the toner bottle unit holding the toner bottle is withdrawn from the image forming apparatus body, the shutter closes the opening so that toner stored in the toner containing section does not leak from the opening. When the toner bottle unit is attached to the image forming apparatus body, the shutter opens opening, thereby the toner containing section is communicated with the developing device so that the toner can be supplied to the developing device from the toner containing section.
As shown in FIGS. 42 and 43, the toner bottle unit 80 of the Japanese Patent Registration No. 3492856 is attached to the image forming apparatus body by pushing one end of the operation lever 81 arranged almost on the longitudinal axis of the cylindrical toner bottle 85 toward the image forming apparatus. Thus, when the toner bottle unit 80 is attached to the image forming apparatus body, a direction of a pushing force applied to the operation lever 81 sometimes deviates from the axis of the toner bottle, for example, inclining downwardly from the axis in a direction (f) as shown by a two-doted line in FIG. 44. In such a situation, a component of the pushing force can be divided into horizontal and vertical directions as shown by arrows (g) and (h). Specifically, a force is applied to the end of the operation lever 81 not only in the axis direction but also in the vertical direction. A distance (I) between the rotary shaft 86 and the operation lever 81 is set to a prescribed level enabling a user to swing the operation lever 81 with a small power considering a moment of a force around the rotary shaft 86.
Accordingly, when only a slight power is applied in the vertical direction deviating from the shaft axis as shown by an arrow (f), the operation lever 81 is easily swung, and the cap-opening device 82 removes the cap 83 from the toner bottle 85 in conjunction therewith. As a result, toner scatters from the toner bottle 85 during the attachment of the toner bottle unit 80 to the image forming apparatus body as shown in FIG. 45.
In the image forming apparatus of the JPO2006-259228, toner adheres to the surface of the shutter as time elapses. Thus, when the shutter closes the opening, the toner adherence creates a gap at a contact portion between the flat surface of the shutter and the circumferential edge of the opening. Accordingly, when the toner bottle unit is attached and detached to and from the image forming apparatus body for the purpose of replacing the toner bottle, the toner remaining in the toner containing section leaks therefrom via the gap.